[Paint Preview] Add delay before removing player

This adds a finch-controllable delay before removing the paint preview
player on tab first paint, for startup experiment.

It also increases the snackbar duration from 5 to 8 seconds.

Bug: 1110360
Change-Id: I46d12eae990be2695af4ae7ca2ca27eb28f70902
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2323822Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Commit-Queue: Mehran Mahmoudi <mahmoudi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792314}

chrome/browser/paint_preview/android/java/src/org/chromium/chrome/browser/paint_preview/TabbedPaintPreviewPlayer.java

@@ -5,12 +5,14 @@
 package org.chromium.chrome.browser.paint_preview;
 
 import android.content.res.Resources;
+import android.os.Handler;
 import android.view.View;
 
 import androidx.annotation.Nullable;
 
 import org.chromium.base.UserData;
 import org.chromium.base.metrics.RecordUserAction;
+import org.chromium.chrome.browser.flags.ChromeFeatureList;
 import org.chromium.chrome.browser.paint_preview.services.PaintPreviewTabService;
 import org.chromium.chrome.browser.paint_preview.services.PaintPreviewTabServiceFactory;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
@@ -33,7 +35,9 @@ public class TabbedPaintPreviewPlayer implements TabViewProvider, UserData {
     public static final Class<TabbedPaintPreviewPlayer> USER_DATA_KEY =
             TabbedPaintPreviewPlayer.class;
 
-    private static final int SNACKBAR_DURATION_MS = 5 * 1000;
+    private static final int SNACKBAR_DURATION_MS = 8 * 1000;
+    private static final int DEFAULT_INITIAL_REMOVE_DELAY_MS = 400;
+    private static final String INITIAL_REMOVE_DELAY_PARAM = "initial_remove_delay_ms";
 
     private Tab mTab;
     private PaintPreviewTabService mPaintPreviewTabService;
@@ -60,12 +64,23 @@ public class TabbedPaintPreviewPlayer implements TabViewProvider, UserData {
             public void didFirstVisuallyNonEmptyPaint(Tab tab) {
                 if (!isShowingAndNeedsBadge()) return;
 
+                long delayMs = ChromeFeatureList.getFieldTrialParamByFeatureAsInt(
+                        ChromeFeatureList.PAINT_PREVIEW_SHOW_ON_STARTUP, INITIAL_REMOVE_DELAY_PARAM,
+                        DEFAULT_INITIAL_REMOVE_DELAY_MS);
+                // Delay removing paint preview after didFirstVisuallyNonEmptyPaint and no user
+                // interaction by |delayMs|. This is to account for 'heavy' pages that take a while
+                // to finish painting and avoid having flickers when switching from paint preview
+                // to the live page.
+                new Handler().postDelayed(() -> {
+                    if (!isShowingAndNeedsBadge()) return;
+
                     if (!mHasUserInteraction) {
                         removePaintPreview();
                         return;
                     }
 
                     showSnackbar();
+                }, delayMs);
             }
 
             @Override